Communication system and communication method

ABSTRACT

One power control means  14  controls a transmitting power according to a control command to a mobile terminal which accesses one task when radio communication is performed with the mobile terminals in the corresponding sector, and a power control unit  15  gives a control command to each of a plurality of power control means  14  to collectively control the transmitting power to mobile terminals in a plurality of sectors, thereby for accomplishing reduction of interference and elimination of traffic maldistribution in a cell consisting of a plurality of sectors when radio communication is performed with mobile terminals for each sector.

SPECIFICATION

[0001] 1.Technical Field

[0002] This invention is related to a communication system and acommunication method, and particularly to control of transmitting power.

[0003] 2. Background Art

[0004]FIG. 1 shows a partial construction in a communication system ofCDMA (Code Division Multiple Access), in which reference numeral 1 is aPSTN (Public Switched Telephone Network), 2 is an RNC (Radio Networkcontrol apparatus), 3 is a plurality of BTS's (Basic Station), 4 is amobile terminal which performs radio communication between the BTS 3,and 5 is a cell which is a range allowing communication between each BTS3.

[0005] Now, the operation is described.

[0006] When the user of any mobile terminal 4 in a cell 5, which iscapable of radio communication by down-link transmitting power, inputs atelephone number to originate a call (access), the BTS 3 correspondingto the cell 5 responds to the call and receives the radio signal fromthe mobile terminal 4. And, it identifies the mobile terminal 4 from thedemodulated signal obtained by demodulating the received radio signal,and identifies the called terminal from the telephone number containedin the demodulated signal. Then, the connection request information forthem is transmitted to the RNC 2.

[0007] RNC 2 responds to the connection request information to performthe connection control between the originating mobile terminal 4 and thecalled terminal. That is, if the called terminal is in another network,that information is sent to the PSTN 1. Or, if the called terminal is amobile terminal 4 in the same radio network, the connection requestinformation is sent to all the accommodated BTS's 4. Each BTS 4originates a call to the mobile terminal 4 existing in the correspondingcell 5 to call the telephone number.

[0008] If the mobile terminal 4 corresponding to this telephone numberexists in the cell allowing radio communication by the transmittingpower of any BTS 3, it responds to the call to notify the user of anincoming call. And, if the user responds to the incoming call, acommunication channel is established between the mobile terminal 4,which is the calling terminal, and the mobile terminal 4 which is thecalled terminal, and voice data is transmitted and received. If one orboth in communication move from the region of the current cell into theregion of another cell, the BTS 3 corresponding to the current cellsenses that, and notifies the RNC 2 of the movement of the mobileterminal 4. The RNC 2 performs so-called handoff processing in responseto the notification.

[0009] Further, the RNC 2 defines the maximum reference value and theminimum reference value of the mobile terminal 4 that can access eachaccommodated BTS 3, and sends common pilot transmitting power to controlthe transmitting power to the mobile terminal. As a result, as shown inFIG. 2, the BTS 4 adjusts the radius (field strength of transmittingpower) of the corresponding cell 5. For instance, if the radius of thecell is assumed to be R1 when the number of mobile terminals 4 (referredto as “traffic number” is in a prescribed range, the radius of the cell5 is set to R2 to expand the range allowing communication if the numberof mobile terminals 4 decrease below the minimum reference value.Conversely, if the number of mobile terminals 4 exceeds the maximumreference value, the radius of the cell is set to R3 to narrow the rangeallowing communication.

[0010]FIG. 3 is a flowchart showing the operation of the cell radiusadjustment, and in the figure, it is determined whether or not thetraffic number has exceeded the maximum reference value (step ST1), andthe cell radius is reduced if exceeded (step ST2). Further, it isdetermined whether or not the traffic number had decreased below theminimum reference value (step ST3), and the cell radius is extended ifdecreased (step ST4).

[0011] However, in the above conventional communication system andcommunication method, since the radius is reduced or extended for acertain cell alone, there is a problem that interference or trafficmaldistribution in a plurality of cells occurs. Further, since themobile terminals 4 do not always concentrically exist around the BTS 3,there is a problem that traffic control is insufficient with theconventional power control by adjustment of the cell radius.

[0012] The present invention was accomplished to solve the abovedescribed problems, and it aims to reduce interference and eliminatetraffic maldistribution in a plurality of cells. Further, it aims toenable sufficient traffic control in a cell or in a plurality of cells.

DISCLOSURE OF INVENTION

[0013] The communication system according to the present invention isadapted to have a power control means for controlling a transmittingpower according to a control command to a mobile terminal which accessesone radio area when radio communication is performed between the mobileterminal in the one radio area; and a collective control means forgiving the control command to each of a plurality of the power controlmeans to collectively control the transmitting power to mobile terminalsin a plurality of the radio areas.

[0014] This provides an advantage that, when radio communication isperformed with a mobile terminal for each radio area, reduction ofinterference and elimination of traffic maldistribution in a pluralityof radio areas can be accomplished. Further, there is also an advantagethat sufficient traffic control can be performed in a radio area or in aplurality of radio areas.

[0015] In the communication system according to the present invention,the power control means is a power computing unit for computing thetransmitting power according to a control command to a mobile terminalaccessing one sector of a cell consisting of plurality of sectors whenradio communication is performed with the mobile terminals in the onesector, and the collective control means is a base station foraccommodating a plurality of power control means and giving the controlcommand to each of plurality of the power control means to collectivelycontrol the transmitting power to mobile terminals in the cell.

[0016] This provides an advantage that reduction of interference andelimination of traffic maldistribution in one cell consisting of aplurality of sectors can be accomplished when radio communication ismade between a mobile terminal for each sector. Further, there is alsoan advantage that sufficient traffic control can be performed in eachsector.

[0017] In the communication system according to the present invention,the power control means is a base station for controlling thetransmitting power according to a control command to a mobile terminalaccessing one cell when radio communication is performed with the mobileterminals in the one cell, and the collective control means is a radionetwork control apparatus for accommodating a plurality of base stationsand giving the control command to each of plurality of the base stationsto collectively control the transmitting power to mobile terminals in aplurality of the cells. Further, there is also an advantage thatsufficient traffic control can be performed in each cell.

[0018] This provides an advantage that reduction of interference andelimination of traffic maldistribution in a plurality of cells can beaccomplished when radio communication is made between a mobile terminalfor each cell.

[0019] In the communication system according to the present invention,the power control means controls the transmitting power to a mobileterminal for each period of a slot which is a predetermined amount oftransmit-receive data, or of a frame consisting of a plurality of slots,for a common pilot channel transmitting power given from the collectivecontrol means.

[0020] This provides an advantage that the transmitting power in aplurality of radio areas can be controlled at high speed.

[0021] In the communication system according to the present invention,the collective control means is notified of a value of the number ofmobile terminals received by each power control means, and determinesthe control command to be given to each power control means based on thenotified value.

[0022] This provides an advantage that traffic load can be distributedin a wide range.

[0023] In the communication system according to the present invention,the collective control means gives the control command to each powercontrol means so as to prevent the occurrence of absence of transmittingpower between adjacent radio areas and overlapping of transmitting powerbetween the adjacent radio areas in a plurality of collectivelycontrolled radio areas.

[0024] This provides an advantage that reduction of interference andelimination of traffic maldistribution between the adjacent radio areascan be accomplished.

[0025] In the communication system according to the present invention,the collective control means grasps information on a common pilotchannel transmitting power in each power control means, and controls areference signal to interference power ratio and a reference number ofrandom access channels in the each power control means.

[0026] This provides an advantage that optimum power control can beperformed between the adjacent radio areas.

[0027] In the communication system according to the present invention,the collective control means defines a range of the maximum value andthe minimum value of the common pilot channel transmitting power in eachpower control means, and if any accommodated power control meansautonomously performs a power control in the corresponding radio area,it controls the common pilot channel transmitting power within thedefined range for a power control means corresponding to the radio areasadjacent to the radio area.

[0028] This provides an advantage that the transmitting power in anindividual radio area is controlled at high speed, and reduction ofinterference and elimination of traffic maldistribution among aplurality of radio areas can be accomplished.

[0029] A communication method according to the present invention is togive a control command to a power control means performing radiocommunication with mobile terminals in one radio area to control atransmitting power to each mobile terminals accessing the one radioarea, thereby for collectively controlling the transmitting power tomobile terminals in a plurality of radio areas.

[0030] This provides an advantage that reduction of interference andelimination of traffic maldistribution in a plurality of radio areas canbe accomplished when radio communication is performed between a mobileterminal for each radio area. Further, there is also an advantage thatsufficient traffic control can be performed in a radio area and in aplurality of radio areas.

[0031] In the communication method according to the present invention,the power control means controls the transmitting power to the mobileterminal for each period of a slot which is a predetermined amount oftransmit-receive data, or of a frame consisting of a plurality of slots,for a common pilot channel transmitting power given from asuperordinate.

[0032] This provides an advantage that the transmitting power in aplurality of radio areas can be controlled at high speed.

[0033] In the communication method according to the present invention,upon notification of a value of the number of mobile terminals receivedby each of a plurality of the power control means, a control command tobe given to each power control means is determined based on the notifiedvalue.

[0034] This provides an advantage that traffic load can be distributedin a wide range.

[0035] In the communication method according to the present invention,the control command is given to each of the plurality of power controlmeans so as to prevent the occurrence of absence of transmitting powerbetween adjacent radio areas and overlapping of transmitting powerbetween the adjacent radio areas in a plurality of collectivelycontrolled radio areas.

[0036] This provides an advantage that reduction of interference andelimination of traffic maldistribution between the adjacent radio areascan be accomplished.

[0037] The communication method according to the present invention,information on a common pilot channel transmitting power in each of theplurality of power control means are grasped to control a referencesignal to interference power ratio and a reference number of randomaccess channels in each power control means.

[0038] This provides an advantage that optimum power control can beperformed between the adjacent radio areas.

[0039] In the communication method according to the present invention, aranges of the maximum value and minimum value of the common pilotchannel transmitting power in each of the plurality of power controlmeans are defined, and if any power control means autonomously performsa power control in the corresponding radio area, the common pilotchannel transmitting power is controlled within the defined ranges forthe power control means corresponding to the radio areas adjacent to theradio area.

[0040] This provides an advantage that the transmitting power in anindividual radio area can be controlled at high speed, and reduction ofinterference and elimination of traffic maldistribution among aplurality of radio areas can be accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041]FIG. 1 is a diagram showing a partial construction in theconventional CDMA communication system;

[0042]FIG. 2 is a diagram showing the adjustment of the cell radius inpower control by the conventional communication system;

[0043]FIG. 3 is a flowchart showing the adjustment of the cell radius inthe conventional communication system;

[0044]FIG. 4 is a diagram showing the cell structure of thecommunication system in the embodiment 1 for carrying out the presentinvention;

[0045]FIG. 5 is a block diagram showing the construction of the BTS ofthe communication system in the embodiment 1 for carrying out thepresent invention;

[0046]FIG. 6 is a block diagram showing the construction of the powercomputing unit in FIG. 5;

[0047]FIG. 7 is flowchart showing the operation of the communicationsystem in the embodiment 1 for carrying out the present invention;

[0048]FIG. 8 is a diagram showing the communication system in theembodiment 2 for carrying out the present invention; and

[0049]FIG. 9 is a block diagram showing the power computing unit in theRNC in FIG. 8.

BEST MODE FOR CARRYING OUT THE INVENTION

[0050] Now, to describe the present invention in more detail, the bestmode for carrying out the present invention is described according tothe accompanying drawings.

Embodiment 1

[0051]FIG. 4 is a diagram showing a cell structure of the communicationsystem in embodiment 1 for carrying out the present invention, and inthe figure, reference numeral 11 denotes a BTS (Base Station) connectedto an RNC (Radio Network control apparatus), and 12 denotes a cellconsisting of six sectors (a plurality of radio areas) managed by theBTS 11.

[0052]FIG. 5 is a block diagram showing the construction of the BTS 11of the communication system in the embodiment 1 for carrying out thepresent invention, and in the figure, reference numeral 13 denotes sixtransceiver units corresponding to the respective sectors (sectors 1 to6) of the cell 12, 14 denotes six power computing units (power controlmeans) corresponding to the respective transceiver units 13, 15 denotesa power control unit (central control means) connected to the respectivepower computing units 14, and a to d are signals to be sent and receivedinside the BTS 11 and between the RNC (not shown). FIG. 6 is a blockdiagram showing the construction of the power computing unit 14 in FIG.5, in which 16 denotes a comparator, 17 denotes a correction amountcomputing unit, 18 denotes an adder, and e and f are signals to be sentand received in the power computing unit 14.

[0053] Now, the operation is described.

[0054] Sent from the RNC, not shown, to the power control unit 15 of theBTS 11 are a power indicating signal a of the common pilot channeltransmitting power (hereinafter referred to as “CPICH transmittingpower”) and a reference indicating signal b consisting of a referencesignal to interference power ratio (hereinafter referred to as “SIR”)and a reference number of random access channels (hereinafter referredto as “reference RACH number”). That is, a control command set by thesuperordinate RNC is transmitted to the subordinate BTS 11. The powercontrol unit 15 gives the received power indicating signal a andreference indicating signal b to each of the six power computing units14. The respective power control units 14 give the power indicatingsignal a (after the correction described later, power indicating signald) to the respective corresponding transceiver units 13, and stores thereference indicating signal b in the memory (not shown) of thecomparator 16 shown in FIG. 6.

[0055] Each transceiver unit 13 controls the transmitting power to amobile, or the down-link transmitting power, according to the powerindicating signal a. For instance, in urban areas where the number ofmobile terminals existing in the corresponding sector is large, therange of the sector or the transmitting power is small, and in suburbanand rural areas where the number of mobile terminals is small, the rangeof the sector (transmitting power) is large. Accordingly, the range ofthe cell 12 made up of six sectors is controlled by the power indicatingsignal a.

[0056] By regionally and statistically limiting the number of accessiblemobile terminals by such power control, the so-called traffic number iscontrolled. The reference SIR and reference RACH number forming thereference indicating signal b stored in the comparator 16 of the powercomputing unit 14 is pertinent to this traffic control. This point willbe further described later.

[0057] When each transceiver unit 13 receives the access from a mobileterminal existing in the corresponding sector, it measures the receptionsignal to interference ratio (hereinafter referred to as “receptionSIR”). The transceiver unit 13 supplies the measured reception SIR tothe corresponding power computing unit 14.

[0058] The power computing unit 14 stores the reception SIR suppliedfrom the transceiver unit 13 in the memory of the comparator 16. Thecomparator 16 compares the stored reception SIR with the reference SIR.The comparator 16 determines whether the reception SIR is larger orsmaller than the reference SIR. And, if the reception SIR is smallerthan the reference SIR, it inputs a plus compare signal e to thecorrection amount computing unit 17, and if the reception SIR is largerthan the reference SIR, it inputs a minus compare signal e to thecorrection amount computing block 17.

[0059] The correction amount computing block 17 computes the correctionamount based on the inputted compare signal e, and inputs a correctionsignal f indicating the computed correction amount to the adder 18. Theadder 18 adds the correction amount of the correction signal f to theCPICH transmitting power supplied from the RNC through the power controlunit 15, and supplies the power indicating signal d of the correctedCPICH transmitting power to the transceiver unit 13 and the powercontrol unit 15.

[0060] As a result, if the reception SIR is smaller than the referenceSIR, or if the mobile terminals in the sector are less than thereference, the power computing unit 14 performs control to increase thedown-link transmitting power to widen the range of the sector.Conversely, if the reception SIR is larger than the reference SIR, or ifthe mobile terminals in the sector is more than the reference, the powercomputing unit 14 performs control to reduce the down-link transmittingpower to narrow the range of the sector.

[0061] In this case, the power computing unit 14 controls thetransmitting power to mobile terminals for each period of a slot, whichis a predetermined amount of transmit/receive data, or a frameconsisting of plurality of slots, for the CPICH transmitting power givenfrom the power control unit 15. Further, the down-link power control bythe individual power computing unit 14 is autonomously performed.

[0062] If the power control unit 15 is supplied with the powerindicating signal d after correction from any power computing unit 14,it performs power control in the adjacent sectors. FIG. 7 is a flowchartshowing the operation of the adjacent sector control processing. First,the value of a pointer n specifying a sector is set to 1 to specify thesector 1 (step ST11). And, the loop of steps ST12 to ST15 is repeatedwhile incrementing the pointer n.

[0063] That is, it is determined whether or not the CPICH transmittingpower of the sector (n) specified by the pointer n has changed (stepST12), and if there is no change, the value of the pointer n isincremented (step ST13). And, it is determined whether or not the valueof n has exceeded 6 (step ST14). If the value of n is 6 or smaller, theprocess goes to step ST12 to determine whether or not the CPICHtransmitting power of the sector (n) has changed. If the CPICHtransmitting power has changed, the CPICH transmitting power of theadjacent sectors is controlled by the RNC within the range of thespecified maximum/minimum CPICH transmitting power (step ST15).

[0064] As obvious from the foregoing, in accordance with the embodiment1, since there are provided the power computing unit 14 for controllingthe transmitting power to a mobile terminal accessing one task accordingto a control command when radio communication is performed between amobile terminal in one sector, and the power control unit 15 forcollectively controlling the transmitting power to mobile terminals inthe cell 12 of a plurality of sectors by giving a control command toeach of the plurality of power computing unit 14, there is an advantagethat reduction of interference and elimination of trafficmaldistribution in the cell consisting of a plurality of sectors can beaccomplished. Further, there is also an advantage that sufficienttraffic control can be performed in a sector and a cell.

[0065] In the embodiment 1, since the power computing unit 14 controlsthe transmitting power to a mobile terminal for each period of slot,which is a predetermined amount of transmit/receive data, or a frameconsisting of a plurality of slots, for the CPICH transmitting powergiven from the power control unit 15, there is an advantage that thetransmitting power in a plurality of radio areas can be controlled athigh speed.

[0066] Further, in the embodiment 1, since the power control unit 15 isnotified of the number of mobile terminals received by each powercomputing unit 14, and determines a control command, or CPICHtransmitting power, to be given to each power computing unit 14 based onthe notification, there is an advantage that traffic load can bedistributed in a wide range.

[0067] Further, in the embodiment 1, since the power control unit 15gives a control command to each power computing unit 14 so as to preventthe occurrence of absence of transmitting power in the adjacent sectorsin a plurality of collectively controlled sectors and overlapping oftransmitting power between the adjacent sectors, there is an advantagethat reduction of interference and elimination of trafficmaldistribution between the adjacent sectors can be accomplished.

[0068] Further, in the embodiment 1, since the power control unit 15defines the ranges of the maximum value and minimum value of the CPICHtransmitting power in each power computing unit 14, and if anyaccommodated power computing unit 14 autonomously performs power controlin the corresponding sector, then it controls the CPICH transmittingpower within the defined ranges for the power computing units 14corresponding to the sectors adjacent such sector, there is an advantagethat the transmitting power in each sector can be controlled at highspeed, and reduction of interference and elimination of trafficmaldistribution among cells consisting of plurality of sectors can beaccomplished.

[0069] Further, as a variation of the embodiment 1, the power controlunit 15 may grasp the information on the CPICH transmitting power ineach power computing unit 14 to control the reference SIR and referenceRACH number in each power computing unit 14. In this case, there is anadvantage that optimum power control can be performed between theadjacent radio areas.

Embodiment 2

[0070]FIG. 8 is a diagram showing the communication system in theembodiment 2 for carrying out the present invention, and in the figure,19 denotes an RNC (central control means), and 20 denotes three BTS's(power control means) connected to the RNC 19. The respective BTS's 20perform radio communication with mobile terminals in the respectivecorresponding cells 1, 2, and 3 (a plurality of radio areas). FIG. 9 isthe power computing unit in the RNC 19 in FIG. 8, and in the figure, 21denotes a power computing unit, 22 denotes a comparator, 23 denotes acorrection computing unit, and 24 denotes an adder. g to m1, m2, and m3are signals to be sent and received within the RNC 19 and between theRNC 19 and the respective BTSIs 20.

[0071] Now, the operation is described.

[0072] Sent to the RNC 19 from superordinate of the RNC 19 are the powerindicating signal g of the CPICH transmitting power, and the referenceindicating signal h consisting of the reference SIR and reference RACHnumber. That is, the control command set by superordinate is sent to thesubordinate RNC 19. The RNC 19 gives the received power indicatingsignal g and reference indicating signal h to the power computing unit21 within it. The power computing unit 21 gives the power indicatingsignals m1, m2, and m3 to the three BTS's 20, respectively, and storesthe reference indicating signal h in the memory (not shown) of thecomparator 22.

[0073] The respective BTS's 20 control the transmitting power ordown-link transmitting power to mobile terminals based on the powerindicating signals m1, m2, and m3. Accordingly, the ranges of the threecells 1, 2, and 3 are controlled by the power indicating signals m1, m2,and m3, respectively. And, each BTS 20 measures the reception SIR whenit receives access from a mobile terminal existing in the correspondingcell. The measurement of the reception SIR allows the measurement of thenumber of mobile terminals existing in the corresponding sector. TheBTS's 20 send measuring signals i1, i2, and i3 representing the measuredreception SIR's to the RNC 19.

[0074] The power computing unit 21 of the RNC 19 stores the measurementsignals i1, i2, and i3 received from the respective BTS's 20 in thememory of the comparator 22. The comparator 22 compares the storedreference SIR with the respective reception SIR's selected sequentially.The comparator 22 determines whether the reception SIR is larger orsmaller than the reference SIR. And, if the reception SIR is smallerthan the reference SIR, it inputs a plus compare signal j (forinstance, 1) to the correction amount computing unit 23, and if thereception SIR is larger than the reference SIR, it inputs a minuscompare signal j (for instance, 0) to the correction amount computingunit 23.

[0075] The correction amount computing block 23 computes a correctionamount based on the inputted compare signal j, and inputs a correctionsignal k representing the computed correction amount to the adder 24.The adder 24 adds the correction amount to the CPICH transmitting powersupplied from superordinate, and sends the power indicating signal (forinstance, m2) of the corrected CPICH transmitting power to the BTS 20.This changes the transmitting power of the corresponding BTS 20, and therange of the corresponding cell (for instance, cell 2) changes. Further,also to the BTS 20 corresponding to the cells (for instance, cell 1 andcell 3 adjacent to that cell, the power indicating signals (forinstance, m1 and m3) of the corrected CPICH transmitting power are sent.

[0076] That is, the RNC 19 determines whether or not the CPICHtransmitting power has changed in a cell in any BTS 20, and if changed,it controls the CPICH transmitting power of the adjacent cells withinthe range of the maximum/minimum CPICH transmitting power specified bysuperordinate.

[0077] As obvious from the foregoing, in accordance with the embodiment2, since there are provided the BTS 20 for controlling the transmittingpower to a mobile terminal accessing one cell according to a controlcommand when radio communication is performed between mobile terminalsin one cell, and the RNC 19 for giving a control command to each of aplurality of BTS's to collectively control the transmitting power tomobile terminals in a plurality of cells, there is an advantage thatreduction of interference and elimination of traffic maldistribution ina plurality of cells can be accomplished when radio communication isperformed between mobile terminals for each cell. There is also anadvantage that sufficient traffic control can be performed in a cell orin a plurality of cells.

[0078] Further, in the above embodiment 2, if the RNC 19 is made tocorrespond to the BTS 11 in the embodiment 1, and the plurality of BTS's20 are made to correspond to the power computing unit 14 in theembodiment 1, then each sector in the embodiment 1 corresponds to eachcell in the embodiment 2. Accordingly, the effect of controlling thedown-link transmitting power to each cell and controlling the down-linktransmitting power to a plurality of cells in the embodiment 2 is thesame as the effect of controlling the down-link transmitting power toeach sector and controlling the down-link transmitting power to one cellconsisting of plurality of sectors in the embodiment 1.

Industrial Applicability

[0079] As described above, the communication system and communicationmethod according to the present invention is suitable for a system inwhich one power control means controls the transmitting power to amobile terminal accessing one sector (or cell) according to a controlcommand when radio communication is performed between a mobile terminalin the corresponding sector (cell), and the collective control meansgives a control command to each of the plurality of power control meansto collectively control the transmitting power to mobile terminals in aplurality of sectors (cells), thereby for accomplishing reduction ofinterference and elimination of traffic maldistribution in the pluralityof sectors (or cells) when radio communication is performed betweenmobile terminals for each sector.

What is claimed is:
 1. A communication system comprising; a powercontrol means for controlling a transmitting power according to acontrol command to a mobile terminal which accesses one radio area whenradio communication is performed between the mobile terminal in said oneradio area; and a collective control means for giving said controlcommand to each of a plurality of said power control means tocollectively control the transmitting power to mobile terminals in aplurality of said radio areas.
 2. The communication system according toclaim 1, wherein said power control means is a power computing unit forcomputing the transmitting power according to a control command to amobile terminal accessing one sector of a cell consisting of pluralityof sectors when radio communication is performed with said mobileterminals in said one sector, and said collective control means is abase station for accommodating a plurality of power control means andgiving said control command to each of plurality of said power controlmeans to collectively control the transmitting power to mobile terminalsin said cell.
 3. The communication system according to claim 1, whereinsaid power control means is a base station for controlling thetransmitting power according to a control command to a mobile terminalaccessing one cell when radio communication is performed with saidmobile terminals in said one cell, and said collective control means isa radio network control apparatus for accommodating a plurality of basestations and giving said control command to each of plurality of saidbase stations to collectively control the transmitting power to mobileterminals in a plurality of said cells.
 4. The communication systemaccording to claim 1, wherein said power control means controls thetransmitting power to a mobile terminal for each period of a slot whichis a predetermined amount of transmit-receive data, or of a frameconsisting of a plurality of slots, for a common pilot channeltransmitting power given from said collective control means.
 5. Thecommunication system according to claim 1, wherein said collectivecontrol means is notified of a value of the number of mobile terminalsreceived by each power control means, and determines the control commandto be given to each power control means based on said notified value. 6.The communication system according to claim 1, wherein said collectivecontrol means gives said control command to each power control means soas to prevent the occurrence of absence of transmitting power betweenadjacent radio areas and overlapping of transmitting power between theadjacent radio areas in a plurality of collectively controlled radioareas.
 7. The communication system according to claim 6, wherein saidcollective control means grasps information on a common pilot channeltransmitting power in each power control means, and controls a referencesignal to interference power ratio and a reference number of randomaccess channels in said each power control means.
 8. The communicationsystem according to claim 7, wherein the collective control meansdefines a range of the maximum value and the minimum value of the commonpilot channel transmitting power in each power control means, and if anyaccommodated power control means autonomously performs a power controlin the corresponding radio area, it controls the common pilot channeltransmitting power within said defined range for a power control meanscorresponding to the radio areas adjacent to said radio area.
 9. Acommunication method for giving a control command to a power controlmeans performing radio communication with mobile terminals in one radioarea to control a transmitting power to each mobile terminals accessingsaid one radio area, thereby for collectively controlling thetransmitting power to mobile terminals in a plurality of radio areas.10. The communication method according to claim 9, wherein said powercontrol means controls the transmitting power to the mobile terminal foreach period of a slot which is a predetermined amount oftransmit-receive data, or of a frame consisting of a plurality of slots,for a common pilot channel transmitting power given from asuperordinate.
 11. The communication method according to claim 9,wherein upon notification of a value of the number of mobile terminalsreceived by each of a plurality of said power control means, a controlcommand to be given to each power control means is determined based onsaid notified value.
 12. The communication method according to claim 9,wherein said control command is given to each of said plurality of powercontrol means so as to prevent the occurrence of absence of transmittingpower between adjacent radio areas and overlapping of transmitting powerbetween the adjacent radio areas in a plurality of collectivelycontrolled radio areas.
 13. The communication method according to claim12, wherein information on a common pilot channel transmitting power ineach of said plurality of power control means are grasped to control areference signal to interference power ratio and a reference number ofrandom access channels in each power control means.
 14. Thecommunication method according to claim 13, wherein a ranges of themaximum value and minimum value of the common pilot channel transmittingpower in each of said plurality of power control means are defined, andif any power control means autonomously performs a power control in thecorresponding radio area, the common pilot channel transmitting power iscontrolled within said defined ranges for the power control meanscorresponding to the radio areas adjacent to said radio area.